Reclosers and switches currently used for outdoor power distribution systems include sophisticated protection and control electronics that need to be configured extensively for specific customer applications. Large utilities maintain a small number of application engineering experts that have the knowledge and expertise to configure these devices. However, a large number of potential customers, such as small municipal utilities or co-ops, do not have the requisite knowledge and capability to configure such sophisticated devices. Consequently small utilities and co-ops can be reluctant to introduce more sophisticated power system applications that might improve their services. Large utilities may experience similar problems.
Even for the larger utility customers, the range of features available for feeder automation communications and protection can be overwhelming. Many power protection engineers do not have the necessary knowledge to properly configure the newer communication schemes now available for feeder automation. Furthermore, many of the protection and monitoring functions are not applied, since users do not know how to set them up.
In the past, distribution protection devices, such as hydraulic reclosers, were fairly simple to set up. With today's more sophisticated feeder automation systems, utilities now need to have expertise in the areas of distribution protection, operations and communications. As utilities continue to cut costs and as experienced engineers retire, more of the functions typically performed by more experienced engineers are delegated to entry-level engineers and technicians. Another problem is that engineers and technicians may be unfamiliar with functionality of the intelligent electronic devices they are configuring and operating, and may underutilize capabilities of the devices.
An existing method for setting a protection device involves a utility engineer determining the appropriate protection curve settings for each device on a distribution feeder, the engineer entering those settings into a settings software tool, and downloading the settings to each respective intelligent electronic device (IED) on the distribution feeder. The utility engineer can use a separate software tool to graphically plot the protection curves for more efficient coordination.
An IED is a microprocessor-based electronic device that is capable of sending control signals to switching devices, such as circuit breakers, reclosers, and switches in power systems, both on the distribution network and the transmission network. Many IEDs in use today combine control, monitoring, protection, reclosing elements, communications, power quality monitoring, and metering capabilities. The protection functions supported by IEDs include time delay and instantaneous over-current functions for phase and ground elements, sequence directional over-current functions, reclosing functions, over- and under-frequency protection functions, and over-and under-voltage protection functions. The IEDs also support various metering functions; monitoring of voltage sags, swells, and interruptions; fault location algorithms; and oscillographic record storage. Most IEDs are configured locally using the front panel of the IED device or remotely using a settings software tool, which involves configuring hundreds of setting points individually.